1. Field of the Invention
The invention relates generally to pneumatic conveying and dispensing systems and more particularly, to a field-going machine for applying granular chemicals to crop rows especially in combination with a pneumatic seed planter.
2. Prior Art
It is old in the art to dispense seeds or the like from a central hopper to a plurality of tubes by an air stream. Such is shown in U.S. Pat. Nos. 3,804,036 and 3,189,230. The use of an air stream as a material conveyor is shown in a more simple context in U.S. Pat. No. 2,941,842.
Practical problems with such devices would arise in areas of adaptability to a variety of materials to be dispensed. Considerations of adaptability may involve the need for controls which permit the operator to preselect, maintain and/or change operational characteristics from material-to-material. Another practical problem would relate to efficiency of application of the chemical--not only the efficiency as denoted by a variable overall rate of application (note deflector 49 in the '230 patent)--but more precisely to maintain an efficient and uniform rate of application for each row.
A further practical problem in dispensing granular chemicals pneumatically is that the material can attain a moisture content conducive to the formation of lumps. The conveying air stream in itself may not be sufficient to break up the lumps. Accordingly, blockage or intermitent nonuniform flow rates may result. A typical solution to such a problem is to incorporate a mechanical agitator within the hopper to break up the material so that the same will flow uniformly into the air stream. Of course, all mechanical systems are subject to wear, repair and replacement.